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vdev_disk.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/refcount.h>
#include <sys/vdev_disk.h>
#include <sys/vdev_impl.h>
#include <sys/fs/zfs.h>
#include <sys/zio.h>
#include <sys/sunldi.h>
#include <sys/fm/fs/zfs.h>

/*
 * Virtual device vector for disks.
 */

extern ldi_ident_t zfs_li;

typedef struct vdev_disk_buf {
      buf_t vdb_buf;
      zio_t *vdb_io;
} vdev_disk_buf_t;

static int
vdev_disk_open(vdev_t *vd, uint64_t *psize, uint64_t *ashift)
{
      vdev_disk_t *dvd;
      struct dk_minfo dkm;
      int error;
      dev_t dev;
      int otyp;

      /*
       * We must have a pathname, and it must be absolute.
       */
      if (vd->vdev_path == NULL || vd->vdev_path[0] != '/') {
            vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
            return (EINVAL);
      }

      dvd = vd->vdev_tsd = kmem_zalloc(sizeof (vdev_disk_t), KM_SLEEP);

      /*
       * When opening a disk device, we want to preserve the user's original
       * intent.  We always want to open the device by the path the user gave
       * us, even if it is one of multiple paths to the save device.  But we
       * also want to be able to survive disks being removed/recabled.
       * Therefore the sequence of opening devices is:
       *
       * 1. Try opening the device by path.  For legacy pools without the
       *    'whole_disk' property, attempt to fix the path by appending 's0'.
       *
       * 2. If the devid of the device matches the stored value, return
       *    success.
       *
       * 3. Otherwise, the device may have moved.  Try opening the device
       *    by the devid instead.
       *
       * If the vdev is part of the root pool, we avoid opening it by path.
       * We do this because there is no /dev path available early in boot,
       * and if we try to open the device by path at a later point, we can
       * deadlock when devfsadm attempts to open the underlying backing store
       * file.
       */
      if (vd->vdev_devid != NULL) {
            if (ddi_devid_str_decode(vd->vdev_devid, &dvd->vd_devid,
                &dvd->vd_minor) != 0) {
                  vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
                  return (EINVAL);
            }
      }

      error = EINVAL;         /* presume failure */

      if (vd->vdev_path != NULL && !spa_is_root(vd->vdev_spa)) {
            ddi_devid_t devid;

            if (vd->vdev_wholedisk == -1ULL) {
                  size_t len = strlen(vd->vdev_path) + 3;
                  char *buf = kmem_alloc(len, KM_SLEEP);
                  ldi_handle_t lh;

                  (void) snprintf(buf, len, "%ss0", vd->vdev_path);

                  if (ldi_open_by_name(buf, spa_mode, kcred,
                      &lh, zfs_li) == 0) {
                        spa_strfree(vd->vdev_path);
                        vd->vdev_path = buf;
                        vd->vdev_wholedisk = 1ULL;
                        (void) ldi_close(lh, spa_mode, kcred);
                  } else {
                        kmem_free(buf, len);
                  }
            }

            error = ldi_open_by_name(vd->vdev_path, spa_mode, kcred,
                &dvd->vd_lh, zfs_li);

            /*
             * Compare the devid to the stored value.
             */
            if (error == 0 && vd->vdev_devid != NULL &&
                ldi_get_devid(dvd->vd_lh, &devid) == 0) {
                  if (ddi_devid_compare(devid, dvd->vd_devid) != 0) {
                        error = EINVAL;
                        (void) ldi_close(dvd->vd_lh, spa_mode, kcred);
                        dvd->vd_lh = NULL;
                  }
                  ddi_devid_free(devid);
            }

            /*
             * If we succeeded in opening the device, but 'vdev_wholedisk'
             * is not yet set, then this must be a slice.
             */
            if (error == 0 && vd->vdev_wholedisk == -1ULL)
                  vd->vdev_wholedisk = 0;
      }

      /*
       * If we were unable to open by path, or the devid check fails, open by
       * devid instead.
       */
      if (error != 0 && vd->vdev_devid != NULL)
            error = ldi_open_by_devid(dvd->vd_devid, dvd->vd_minor,
                spa_mode, kcred, &dvd->vd_lh, zfs_li);

      /*
       * If all else fails, then try opening by physical path (if available)
       * or the logical path (if we failed due to the devid check).  While not
       * as reliable as the devid, this will give us something, and the higher
       * level vdev validation will prevent us from opening the wrong device.
       */
      if (error) {
            if (vd->vdev_physpath != NULL &&
                (dev = ddi_pathname_to_dev_t(vd->vdev_physpath)) != ENODEV)
                  error = ldi_open_by_dev(&dev, OTYP_BLK, spa_mode,
                      kcred, &dvd->vd_lh, zfs_li);

            /*
             * Note that we don't support the legacy auto-wholedisk support
             * as above.  This hasn't been used in a very long time and we
             * don't need to propagate its oddities to this edge condition.
             */
            if (error && vd->vdev_path != NULL &&
                !spa_is_root(vd->vdev_spa))
                  error = ldi_open_by_name(vd->vdev_path, spa_mode, kcred,
                      &dvd->vd_lh, zfs_li);
      }

      if (error) {
            vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
            return (error);
      }

      /*
       * Once a device is opened, verify that the physical device path (if
       * available) is up to date.
       */
      if (ldi_get_dev(dvd->vd_lh, &dev) == 0 &&
          ldi_get_otyp(dvd->vd_lh, &otyp) == 0) {
            char *physpath, *minorname;

            physpath = kmem_alloc(MAXPATHLEN, KM_SLEEP);
            minorname = NULL;
            if (ddi_dev_pathname(dev, otyp, physpath) == 0 &&
                ldi_get_minor_name(dvd->vd_lh, &minorname) == 0 &&
                (vd->vdev_physpath == NULL ||
                strcmp(vd->vdev_physpath, physpath) != 0)) {
                  if (vd->vdev_physpath)
                        spa_strfree(vd->vdev_physpath);
                  (void) strlcat(physpath, ":", MAXPATHLEN);
                  (void) strlcat(physpath, minorname, MAXPATHLEN);
                  vd->vdev_physpath = spa_strdup(physpath);
            }
            if (minorname)
                  kmem_free(minorname, strlen(minorname) + 1);
            kmem_free(physpath, MAXPATHLEN);
      }

      /*
       * Determine the actual size of the device.
       */
      if (ldi_get_size(dvd->vd_lh, psize) != 0) {
            vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
            return (EINVAL);
      }

      /*
       * If we own the whole disk, try to enable disk write caching.
       * We ignore errors because it's OK if we can't do it.
       */
      if (vd->vdev_wholedisk == 1) {
            int wce = 1;
            (void) ldi_ioctl(dvd->vd_lh, DKIOCSETWCE, (intptr_t)&wce,
                FKIOCTL, kcred, NULL);
      }

      /*
       * Determine the device's minimum transfer size.
       * If the ioctl isn't supported, assume DEV_BSIZE.
       */
      if (ldi_ioctl(dvd->vd_lh, DKIOCGMEDIAINFO, (intptr_t)&dkm,
          FKIOCTL, kcred, NULL) != 0)
            dkm.dki_lbsize = DEV_BSIZE;

      *ashift = highbit(MAX(dkm.dki_lbsize, SPA_MINBLOCKSIZE)) - 1;

      /*
       * Clear the nowritecache bit, so that on a vdev_reopen() we will
       * try again.
       */
      vd->vdev_nowritecache = B_FALSE;

      return (0);
}

static void
vdev_disk_close(vdev_t *vd)
{
      vdev_disk_t *dvd = vd->vdev_tsd;

      if (dvd == NULL)
            return;

      if (dvd->vd_minor != NULL)
            ddi_devid_str_free(dvd->vd_minor);

      if (dvd->vd_devid != NULL)
            ddi_devid_free(dvd->vd_devid);

      if (dvd->vd_lh != NULL)
            (void) ldi_close(dvd->vd_lh, spa_mode, kcred);

      kmem_free(dvd, sizeof (vdev_disk_t));
      vd->vdev_tsd = NULL;
}

int
vdev_disk_physio(ldi_handle_t vd_lh, caddr_t data, size_t size,
    uint64_t offset, int flags)
{
      buf_t *bp;
      int error = 0;

      if (vd_lh == NULL)
            return (EINVAL);

      ASSERT(flags & B_READ || flags & B_WRITE);

      bp = getrbuf(KM_SLEEP);
      bp->b_flags = flags | B_BUSY | B_NOCACHE | B_FAILFAST;
      bp->b_bcount = size;
      bp->b_un.b_addr = (void *)data;
      bp->b_lblkno = lbtodb(offset);
      bp->b_bufsize = size;

      error = ldi_strategy(vd_lh, bp);
      ASSERT(error == 0);
      if ((error = biowait(bp)) == 0 && bp->b_resid != 0)
            error = EIO;
      freerbuf(bp);

      return (error);
}

static void
vdev_disk_io_intr(buf_t *bp)
{
      vdev_disk_buf_t *vdb = (vdev_disk_buf_t *)bp;
      zio_t *zio = vdb->vdb_io;

      /*
       * The rest of the zio stack only deals with EIO, ECKSUM, and ENXIO.
       * Rather than teach the rest of the stack about other error
       * possibilities (EFAULT, etc), we normalize the error value here.
       */
      zio->io_error = (geterror(bp) != 0 ? EIO : 0);

      if (zio->io_error == 0 && bp->b_resid != 0)
            zio->io_error = EIO;

      kmem_free(vdb, sizeof (vdev_disk_buf_t));

      zio_interrupt(zio);
}

static void
vdev_disk_ioctl_free(zio_t *zio)
{
      kmem_free(zio->io_vsd, sizeof (struct dk_callback));
}

static void
vdev_disk_ioctl_done(void *zio_arg, int error)
{
      zio_t *zio = zio_arg;

      zio->io_error = error;

      zio_interrupt(zio);
}

static int
vdev_disk_io_start(zio_t *zio)
{
      vdev_t *vd = zio->io_vd;
      vdev_disk_t *dvd = vd->vdev_tsd;
      vdev_disk_buf_t *vdb;
      struct dk_callback *dkc;
      buf_t *bp;
      int error;

      if (zio->io_type == ZIO_TYPE_IOCTL) {
            /* XXPOLICY */
            if (!vdev_readable(vd)) {
                  zio->io_error = ENXIO;
                  return (ZIO_PIPELINE_CONTINUE);
            }

            switch (zio->io_cmd) {

            case DKIOCFLUSHWRITECACHE:

                  if (zfs_nocacheflush)
                        break;

                  if (vd->vdev_nowritecache) {
                        zio->io_error = ENOTSUP;
                        break;
                  }

                  zio->io_vsd = dkc = kmem_alloc(sizeof (*dkc), KM_SLEEP);
                  zio->io_vsd_free = vdev_disk_ioctl_free;

                  dkc->dkc_callback = vdev_disk_ioctl_done;
                  dkc->dkc_flag = FLUSH_VOLATILE;
                  dkc->dkc_cookie = zio;

                  error = ldi_ioctl(dvd->vd_lh, zio->io_cmd,
                      (uintptr_t)dkc, FKIOCTL, kcred, NULL);

                  if (error == 0) {
                        /*
                         * The ioctl will be done asychronously,
                         * and will call vdev_disk_ioctl_done()
                         * upon completion.
                         */
                        return (ZIO_PIPELINE_STOP);
                  }

                  if (error == ENOTSUP || error == ENOTTY) {
                        /*
                         * If we get ENOTSUP or ENOTTY, we know that
                         * no future attempts will ever succeed.
                         * In this case we set a persistent bit so
                         * that we don't bother with the ioctl in the
                         * future.
                         */
                        vd->vdev_nowritecache = B_TRUE;
                  }
                  zio->io_error = error;

                  break;

            default:
                  zio->io_error = ENOTSUP;
            }

            return (ZIO_PIPELINE_CONTINUE);
      }

      vdb = kmem_alloc(sizeof (vdev_disk_buf_t), KM_SLEEP);

      vdb->vdb_io = zio;
      bp = &vdb->vdb_buf;

      bioinit(bp);
      bp->b_flags = B_BUSY | B_NOCACHE |
          (zio->io_type == ZIO_TYPE_READ ? B_READ : B_WRITE) |
          ((zio->io_flags & ZIO_FLAG_IO_RETRY) ? 0 : B_FAILFAST);
      bp->b_bcount = zio->io_size;
      bp->b_un.b_addr = zio->io_data;
      bp->b_lblkno = lbtodb(zio->io_offset);
      bp->b_bufsize = zio->io_size;
      bp->b_iodone = (int (*)())vdev_disk_io_intr;

      /* ldi_strategy() will return non-zero only on programming errors */
      VERIFY(ldi_strategy(dvd->vd_lh, bp) == 0);

      return (ZIO_PIPELINE_STOP);
}

static void
vdev_disk_io_done(zio_t *zio)
{
      vdev_t *vd = zio->io_vd;

      /*
       * If the device returned EIO, then attempt a DKIOCSTATE ioctl to see if
       * the device has been removed.  If this is the case, then we trigger an
       * asynchronous removal of the device. Otherwise, probe the device and
       * make sure it's still accessible.
       */
      if (zio->io_error == EIO) {
            vdev_disk_t *dvd = vd->vdev_tsd;
            int state = DKIO_NONE;

            if (ldi_ioctl(dvd->vd_lh, DKIOCSTATE, (intptr_t)&state,
                FKIOCTL, kcred, NULL) == 0 && state != DKIO_INSERTED) {
                  vd->vdev_remove_wanted = B_TRUE;
                  spa_async_request(zio->io_spa, SPA_ASYNC_REMOVE);
            }
      }
}

vdev_ops_t vdev_disk_ops = {
      vdev_disk_open,
      vdev_disk_close,
      vdev_default_asize,
      vdev_disk_io_start,
      vdev_disk_io_done,
      NULL,
      VDEV_TYPE_DISK,         /* name of this vdev type */
      B_TRUE                  /* leaf vdev */
};

/*
 * Given the root disk device devid or pathname, read the label from
 * the device, and construct a configuration nvlist.
 */
int
vdev_disk_read_rootlabel(char *devpath, char *devid, nvlist_t **config)
{
      ldi_handle_t vd_lh;
      vdev_label_t *label;
      uint64_t s, size;
      int l;
      ddi_devid_t tmpdevid;
      int error = -1;
      char *minor_name;

      /*
       * Read the device label and build the nvlist.
       */
      if (devid != NULL && ddi_devid_str_decode(devid, &tmpdevid,
          &minor_name) == 0) {
            error = ldi_open_by_devid(tmpdevid, minor_name,
                spa_mode, kcred, &vd_lh, zfs_li);
            ddi_devid_free(tmpdevid);
            ddi_devid_str_free(minor_name);
      }

      if (error && (error = ldi_open_by_name(devpath, FREAD, kcred, &vd_lh,
          zfs_li)))
            return (error);

      if (ldi_get_size(vd_lh, &s)) {
            (void) ldi_close(vd_lh, FREAD, kcred);
            return (EIO);
      }

      size = P2ALIGN_TYPED(s, sizeof (vdev_label_t), uint64_t);
      label = kmem_alloc(sizeof (vdev_label_t), KM_SLEEP);

      for (l = 0; l < VDEV_LABELS; l++) {
            uint64_t offset, state, txg = 0;

            /* read vdev label */
            offset = vdev_label_offset(size, l, 0);
            if (vdev_disk_physio(vd_lh, (caddr_t)label,
                VDEV_SKIP_SIZE + VDEV_BOOT_HEADER_SIZE +
                VDEV_PHYS_SIZE, offset, B_READ) != 0)
                  continue;

            if (nvlist_unpack(label->vl_vdev_phys.vp_nvlist,
                sizeof (label->vl_vdev_phys.vp_nvlist), config, 0) != 0) {
                  *config = NULL;
                  continue;
            }

            if (nvlist_lookup_uint64(*config, ZPOOL_CONFIG_POOL_STATE,
                &state) != 0 || state >= POOL_STATE_DESTROYED) {
                  nvlist_free(*config);
                  *config = NULL;
                  continue;
            }

            if (nvlist_lookup_uint64(*config, ZPOOL_CONFIG_POOL_TXG,
                &txg) != 0 || txg == 0) {
                  nvlist_free(*config);
                  *config = NULL;
                  continue;
            }

            break;
      }

      kmem_free(label, sizeof (vdev_label_t));
      (void) ldi_close(vd_lh, FREAD, kcred);

      return (error);
}

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